Paper
Dalton Transactions
CD2Cl2): δ 7.40–7.39 (m, 11H, o-CH of BPh4 and m- and p-CH
Synthesis of [Rh(MesCaTBn)Cp*Cl]BPh4 (4a). To a solution
of Ph), 7.17 (m, 2H, o-CH of Ph), 7.03 (s, 2H, m-CH of Mes), of 1h (0.219 g, 0.5 mmol) in acetone (25 mL), silver oxide
6.99 (t, J = 7.34 Hz, 8H, m-CH of BPh4), 6.86–6.85 (m, 4H, p-CH (0.08 g, 0.35 mmol) was added and the reaction mixture was
of BPh4), 6.83 (s, 1H, Im-H4), 6.73 (d, 3J = 1.89 Hz, 1H, Im-H5), refluxed for 3 hours under nitrogen. [RhCp*Cl2]2 (0.155 g,
6.64 (s, 1H, Tz-CH), 5.24 (s, 2H, PhCH2), 4.83 (br s, 0.25 mmol) was added and reaction mixture was refluxed for
2H, COD-CH trans N), 4.68 (s, 2H, Im-NCH2), 3.62 (br s, 2H, 1 h and stirred overnight at room temperature. NaBPh4
COD-CH trans to NHC), 2.37 (s, 3H, p-CCH3), 2.25–2.20 (m, 2H, (0.171 g, 0.50 mmol) was added and the reaction mixture was
COD-CHH), 2.07 (s, 6H, o-CCH3), 2.05–1.87 (m, 6H, COD-CHH stirred for another 30 min, followed by filtration through
and COD-CHH) ppm. 13C{1H} NMR (125 MHz, CD2Cl2): δ Celite. The solvent was removed in vacuo to afford a brown
176.21 (d, 1J(Rh-C2) = 50.9 Hz, Im-C2), 164.45 (q, 1JB–C 49.3 Hz, solid. The solid was redissolved in dichloromethane (4 mL)
ipso-C of BPh4), 140.17 (p-C of Mes), 140.08 (Tz-C4′) and pentane (ca. 15 mL) was added to form a yellow precipi-
136.34 (o-CH of BPh4), 135.90 (ipso-C of Mes), 135.52 (o-C of tate. This suspension was cooled down in an ice bath to
Mes), 133.53 (ipso-C of Ph) 129.64 (m-CH of Mes and p-CH of induce further precipitation of the product, which was filtered
Ph), 129.55 (m-CH of Ph), 128.64 (o-CH of Ph), 126.19 (m-CH of and dried under vacuum. Yield: 0.413 g, 87%; m.p. 132 °C;
BPh4), 123.57 (Im-C4), 123.16 (Tz-C5′), 122.62 (Im-C5), 122.32 ESI-MS (ESI+, MeOH), m/z (assignment, %): 630.2 (M, 71),
(p-CH of BPh4), 96.60 (CH of COD trans N), 79.10 (d, 1J (Rh-C) = 631.2 (M, 24), 632.2 (M, 22) amu; calculated for
10.2 Hz, COD-CH trans NHC), 55.71 (s, CH2Ph), 45.12 (s, Im- [C32H38ClN5Rh]+ = 630.19 amu. Elemental analysis: found: C,
NCH2), 32.59 (COD-CH2 trans N), 29.24 (COD-CH2 trans NHC), 69.94; H, 5.90; N, 7.35; calculated for C56H58BClN5Rh: C,
1
21.21 (o-CCH3), 18.56 (p-CCH3) ppm.
69.46; H, 6.25; N, 7.23%. H NMR (500 MHz, C2D2Cl4): δ 7.48
Synthesis of [Rh(MesCaTBn)(CO)2]BPh4 (3a). A suspension (br s, 8H, o-CH of BPh4), 7.45 (m, 3H, m-CH and p-CH of Ph),
of [Rh(MesCaTBn)(COD)]BPh4, 2a, (0.160 g, 0.174 mmol) in 7.26 (m, 2H, o-CH), 7.02 (m, 8H, m-CH of BPh4) 6.98 (s, 1H,
methanol (4 mL) and pentane (20 mL) was degassed via three m2-CH of Mes), 6.96 (s, 1H, m1-CH of Mes), 6.88 (m, 5H, p-CH
cycles of freeze–pump–thaw. The reaction mixture was placed of BPh4 and H4), 6.80 (d, 3JH4–H5 = 1.7 Hz, 1H, H5), 6.57 (s, 1H,
2
under an atmosphere of carbon monoxide using a balloon, the Tz-H5′), 5.48 (d, JH′–H″ = 14.4 Hz, 1H, Tz-NCH′H″), 5.27 (d,
colour of the solid changed from bright yellow to pale yellow 2JH″–H′ = 14.4 Hz, 1H, TzN-CH′H″, 4.58 (d, 2JH′–H″ = 15.9 Hz, 1H,
2
then turned dark orange. The CO balloon was removed and Im-CH′H″), 4.18 (d, JH″–H′ = 15.9 Hz, 1H, Im-NCH′H″, 2.37 (s,
the orange solid was collected by filtration and washed with 3H, p-CH3 of Mes), 2.10 (s, 3H, o1-CCH3 of Mes), 1.98 (s, 3H,
pentane (3 × 5 mL) and dried in vacuo. Yield: 0.138 g; 95%. o2-CCH3 of Mes), 1.31 (s, 15H, CH3 of Cp*) ppm. 13C{1H} NMR
ESI-MS (ESI+, MeOH) m/z (assignment, %): 520.07 ([M − CO + (125 MHz, C2D2Cl4): δ 168.0 (d, 1J(Rh-C) ∼ 55 Hz, C2), 163.6 (q,
MeOH]+, 46), 516.04 ([M]+, 63), 488.06 ([M − CO]+, 100), 460.08 1J (B-C) ∼ 50 Hz, ipso-C of BPh4), 140.6 (Tz-C4′), 140.0 (p-C of
([M − 2 × CO]+, 67) amu. Elemental analysis: found: C, 69.22; Mes), 138.5 (o2-C of Mes), 136.3 (o-C of BPh4), 135.3 (ipso-C
H, 5.29 and N, 8.55; calculated for C48H43BN5O2Rh: C, 68.99; of Mes), 134.5 (o1-C of Mes), 132.9 (m-CH of Ph), 132.8 (ipso-C
H, 5.19 and N, 8.38%. 1H NMR (500 MHz, CD2Cl2): δ 7.42–7.39 of Ph), 129.8 (m2-C of Mes), 129.6 (p-CH of Ph), 128.6 (o-CH of
(br m, 11H, o-CH of BPh4 and p- and m-CH of Ph), 7.25 (d, 3J = Ph), 128.3 (m1-C of Mes), 125.9 (m-CH of BPh4), 125.5 (Im-C5),
6.9 Hz, 2H, o-CH of Ph), 7.05 (s, 2H, m-CH of Mes), 6.98 (t, 3J = 124.2 (Im-C4), 123.8 (Tz-C5′), 122.0 (p-C of BPh4), 98.6 (CCH3
7.2 Hz, 8H, m-CH of BPh4), 6.94 (s, 1H, Im-H4), 6.86 (s, 1H, of Cp*), 55.8 (Tz-NCH′H″), 44.5 (Im-NCH′H″), 21.3 (p-CCH3 of
3
Im-H5), 6.82 (t, J = 6.8 Hz, 4H, p-CH of BPh4), 6.37 (s, 1H, Tz- Mes), 19.8 (o2-CCH3 of Mes), 19.0 (o1-CCH3 of Mes), 9.5 (CH3
H5′), 5.28 (s, 2H, Tz-NCH2), 4.32 (s, 2H, Im-NCH2), 2.37 (s, 3H, of Cp*) ppm.
p-CCH3), 2.02 (s, 6H, o-CCH3) ppm. 13C{1H} NMR (125 MHz,
1
1
Synthesis of Ir(III) complexes
CD2Cl2): δ 184.29 (d, JRh–C = 60.5 Hz, CO), 184.23 (d, JRh–C
=
=
1
1
68.8 Hz, CO), 171.74 (d, J = 46.8 Hz, Im-C2), 164.01 (q, JB–C
The synthesis of [Ir(Cp*)(MesCaTBn)Cl]BPh4 (5a) is presented
49.3 Hz, ipso-C of BPh4), 140.75 (p-CCH3 of Mes), 139.95 (Tz- here. The syntheses of other Ir(III) complexes (5b–c) were per-
C4′), 135.87 (br s, o-CH of BPh4), 135.62 (o-CCH3 of Mes), formed using an analogous method and are provided in the
132.42 (ispo-C of Ph), 129.54 (p-CH and ipso-C of Mes), 129.47 ESI.†
(m-CH of Ph), 129.32 (m-CH of Mes), 128.60 (o-CH of Mes),
Synthesis of [Ir(MesCaTBn)Cp*Cl]BPh4 (5a). To a solution
125.88 (br s, m-CH of BPh4), 123.74 (s, Tz-C5′), 123.54 (Im-C5), of 1h (0.219 g, 0.50 mmol) in acetone (25 mL), silver oxide
122.91 (Im-C4), 122.02 (p-CH of BPh4), 55.73 (Tz-NCH2), 44.20 (0.08 g, 0.35 mmol) was added and the reaction mixture was
(Im-NCH2), 20.87 (p-CCH3), 17.92 (o-CCH3) ppm. FTIR (dcm): refluxed for
ν (CO): 2095 and 2034 cm−1
3 h under nitrogen. [IrCp*Cl2]2 (0.199 g,
.
0.25 mmol) was added, the reaction mixture was refluxed for
1 h and stirred overnight at room temperature. NaBPh4
(0.171 g, 0.50 mmol) was added and reaction mixture was
stirred for another 30 min, followed by filtration through
Synthesis of Rh(III) complexes
The synthesis of [Rh(Cp*)(MesCaTBn)Cl]BPh4 (4a) is presented Celite. The solvent was removed in vacuo to afford a brown
here. The syntheses of the Rh(III) complexes 4b–d were per- solid. The solid was dissolved in DCM (4 mL) and pentane
formed using an analogous method and the details are pro- (ca. 20 mL) was added to form a yellow precipitate. This suspen-
vided in the ESI.
sion was cooled down in an ice bath to further precipitation of
14306 | Dalton Trans., 2013, 42, 14298–14308
This journal is © The Royal Society of Chemistry 2013